CDAK539A12303: Pelabresibin patients with Myelofibrosis who are JAK inhibitor naive
Research type
Research Study
Full title
A Phase 3, Randomized, Double-Blind, Active-Control Study of Pelabresib (DAK539) and Ruxolitinib vs. Placebo and Ruxolitinib in Adult Patients with Myelofibrosis who are JAK inhibitor naive
IRAS ID
1012585
Contact name
Fiona Morris
Contact email
Sponsor organisation
Novartis Pharmaceuticals UK Limited
Research summary
This study is looking at whether a new combination treatment can improve outcomes for adults with myelofibrosis, a rare blood cancer that causes scarring in the bone marrow. This scarring affects how blood cells are made and often leads to an enlarged spleen, anaemia (low red blood cells), and symptoms such as tiredness and night sweats. Current treatments, including ruxolitinib (a Janus‑associated kinase inhibitor, or JAK inhibitor), can help but do not work well enough for everyone.
Researchers want to find out if adding pelabresib, an experimental drug, to ruxolitinib provides better results than ruxolitinib alone. Pelabresib blocks proteins called BET (bromodomain and extra‑terminal domain) proteins, which can activate cancer‑related genes. Earlier studies suggest that combining the two medicines might reduce spleen size and improve symptoms.
Participants will be randomly assigned to receive either pelabresib plus ruxolitinib or placebo (a dummy tablet) plus ruxolitinib. Neither participants nor doctors will know which treatment is given (a “double‑blind” design). The main aims are to see whether the combination reduces spleen size and improves symptoms after 24 weeks. Researchers will also look at blood tests, quality of life, safety, and long‑term disease outcomes.
Adults with myelofibrosis who have not been treated with any JAK inhibitor before may be able to join if they meet clinical criteria, such as having an enlarged spleen and suitable blood counts.
Participants will take the study medicines in 21‑day cycles and attend regular visits for blood tests, physical exams, scans, and questionnaires.
The study is sponsored and funded by Novartis and will take place in multiple hospitals worldwide. The findings may help guide future treatment for people with myelofibrosis.REC name
South Central - Berkshire Research Ethics Committee
REC reference
26/SC/0127
Date of REC Opinion
26 May 2026
REC opinion
Further Information Favourable Opinion